\documentclass{article}
\usepackage{fancybox}
\begin{document}
there we can input something for test
\\
this file was edited with vim
\\
vim have many functions which are very useful and convenient
\\
once you get used to its key
$ \lim = \sum x_i^* = z$
\[
\frac{x}{y}=Z
\]
\section
\begin{eqnarray}
x_i = S^x \\
\frac {\partial x} {\partial y}= zyz
\frac {x_i} 
\end{eqnarray}
\section{basic editing}
split	to split windows
vsplit 	vertical windows
ctrl+w o	other window
ctrl+
\section
\ovalbox{we can use Y to cp a line and p to use it}\\
\ovalbox{here we have some ovalbox}\\

\ovalbox{u can use ctrl+V to copy a rectangle, or use V copy a whole line}\\
\shadowbox{ shadow box}\\

\ovalbox{yaw to yank a word, then p to paste it}\\
\shadowbox{use split to split windows, ctrl+w w to switch, ctrl+w o to swith}\\
\ovalbox{use h-j-k-l to move 4d}\\
\ovalbox{use b-w to move a word for and backward}\\
\ovalbox{V to copy a line,Y to copy a single line}
\ovalbox{use h-j-k-l to move 4d}\\
\end{document}


